app/internal/window: x11 driver

This driver still lacks fling support and dp/sp configuration.

By default, linux builds will try to use the Wayland driver then
fallback to X11 if it fails. Drivers can be disabled by using either the
nowayland or nox11 build tags.

Signed-off-by: Denis Bernard <db047h@gmail.com>

app/internal/window/egl_x11.go

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+// +build linux,!android,!nox11
+
+package window
+
+import "gioui.org/app/internal/gl"
+
+func (w *x11Window) NewContext() (gl.Context, error) {
+	return newContext(w)
+}
+
+func (w *x11Window) eglDestroy() {
+	w.destroy()
+}
+
+func (w *x11Window) eglDisplay() _EGLNativeDisplayType {
+	return _EGLNativeDisplayType(w.display())
+}
+
+func (w *x11Window) eglWindow(visID int) (_EGLNativeWindowType, int, int, error) {
+	return _EGLNativeWindowType(uintptr(w.xw)), w.width, w.height, nil
+}
+
+func (w *x11Window) needVSync() bool { return true }